NEW DELHI (AP) — India's coast guard authorities said Sunday they have seized a massive amount of heroin from a ship off the country's western coast.

The 1,500 kilograms (3,300 pounds) of narcotics was estimated to be worth millions of dollars, and the vessel was believed to be registered in Panama, the agency said.

The ship was seized on Saturday.

Coast guard authorities said this was the biggest seizure of narcotics in recent years, the Press Trust of India reports.

The vessel had eight crew members onboard and was heading for the Alang shipyard in Gujarat state, the agency said. The crew has been detained for questioning.

India falls on a lucrative drug-smuggling route because nearby Afghanistan is a major producer of opium, the main ingredient in heroin.

Details on where the consignment originated and people involved in the smuggling were not immediately known. A joint investigation by the Indian coast guard, intelligence agencies, police and the Navy was underway.